Fuel oil piping system with pressure responsive safety device



June 18, 1963 H, DAVIES, JR 3,094,162

FUEL OIL PIPING SYSTEM WITH PRESSURE RESPONSIVE SAFETY DEvICE Filed Dec. 16, 1959 INVENTOR. Evan H. Dav|es,1r.

ymflw/ United States This invention is a fuel oil piping system which eliminates the need for the normal return line, from the burner back to the oil storage tank, and provides a safety device to eifect the stoppage of oil from being forced into the system should derangement of piping occur.

Among the objects of my invention is to include a safety device, so located in the fuel oil piping system as to effect the stoppage of oil from being forced therein, should any derangement of the piping occur. This provides a safety factor throughout the system.

Another object of my invention is to provide a practical installation of a fuel oil distribution system without the customary return line from the burner back to the fuel oil storage tank, thereby elfecting more economical installation.

My invention also has such other objects, advantages and capabilities as will later more fully appear and which are inherently possessed by this invention.

While I have shown in the accompanying drawings a prefer-red embodiment of my invention, yet it is to be understood that the same is susceptible of modification and change without departing from the spirit of my invention.

Referring to the drawings, FIG. 1 is a diagrammatic broken view of a fuel oil piping system for multiple furnaces embodying my invention; FIG. 2 is a wiring diagram of my pressure switch and its electrical connections; and FIG. 3 is an electric diagram for use with a single furnace.

My invention is applicable to both multiple furnace installations in large industrial establishments, such as werehouses, in which a plurality of furnaces are spaced throughout huge areas, and to single furnace installations.

In a multiple furnace installation, there is a fuel storage tank containing fuel oil. The tank has the usual air vent pipe and fuel fill pipe. Oil is drawn from storage tank 10 by a fuel oil lift pump 11 through suction conduit 12 which has a gate valve 13, a fuel oil strainer 14, a vacuum gauge 15, and a check valve 16. Suction conduit 12 terminates at fuel oil lift pump 11, with pump motor 17 adjacent. From fuel oil lift pump 11, supply conduit 18 carries fuel oil to the burners, as hereinafter set forth. Directly after fuel oil lift pump 11, is a bypass conduit 19 from conduit 18 which includes a pressure gauge 20, a pressure regulating valve 21 and a check valve 22. This bypass conduit 19 merges with suction conduit 12. Conduit 18 has at the top of its vertical riser, from fuel oil lift pump 11, an air venting valve 23. A branch conduit 24, from supply conduit 18 for each furnace, furnishes oil to the oil burner circuit, which includes a gate valve 25, a check valve 26, a pressure regulating valve 27, an oil burner with integral suction pump 28, and an oil pressure relief valve 29. 'It is in parallel with supply conduit 18 and is repeated in a plurality of spaced branch lines 24, each having equipment as called for above, re: oil burner circuit. Located at the most extreme end of supply conduit 18 is an air venting valve 23, which has immediately prior thereto, a pressure switch 30. Prior to pressure switch 30 is a surge chamber 31. This surge chamber 31 is a larger piece of pipe than supply conduit 18, with an increaser fitting from supply conduit 18 and a reducer fitting at its other end.

In operation, oil in supply conduit 18 is in contact with pressure switch 30 at normal pressure to maintain the pressure switch in closed position and keep pump 11 working.

atent Q If, at any time, derangement occurs so that pressure of the oil is lessened on pressure switch 30, this will cause an open electrical circuit, ceasing the operation of pump 11 and the flow of oil.

To my knowledge, my apparatus is different than other piping systems because I have located a fuel oil lift pump (with normal components to prevent excessive pressure), within a closed type piping system and protect the installation with a pressure control switch located adjacent the extreme end of the piping. This pressure control switch causes the stoppage of the lift pump should any derangement occur within the piping system, lessening the oil pressure.

The pressure control switch has immediately prior to it, a surge chamber. This is a piece of pipe between an increaser fitting from the main supply line and a reducer fitting at the other end. It is included in the system to anticipate the initial starting of an oil burner and/or burners. The starting of these burners causes a momentary line drop which would affect the pressure switch.

In multiple furnace type fuel oil piping systems, commonly in practice today, the burner closer to the oil tank has a lesser suction demand on it than has number two, number three, et cetera, located more remote from the fuel oil tank than number one. Therefore, it may readily be seen, that the longevity of the pump for the first unit is more than for number two; number two is more than for number three, et cetcra. Also, in a multiple furnace installation which has a common fuel oil supply without a lift pump, it should be point out that, should more than one burner be in operation at the same time, the pump at each burner would not only have to provide a suc tion head to the burner, but must also fiight other pumps operating within the system. I solve this problem with my construction.

1 have shown herein my means of preventing leakage or discharge of fuel oil inside a building caused by any derangement of its piping system.

In a multiple furnace installation, there is the normal electrical source of supply from a utility company, which is connected by wires to main disconnect switch 32, after which is a push button station 33 (with spring release and indicator lamp), a timer relay 34, an electric magnetic starter 35 for fuel oil lift pump motor 17, and pressure switch 30.

In operation, with main disconnect switch 32 in closed position, the manual depression of push button at 33 causes the timer relay 34 to start its cycle. (The operation of push button at 33, which actuates timer relay 34, is required only at the beginning of heating season, except when derangement of fuel oil system occurs.) The operation of the timer relay 34 starts the fuel oil [lift pump motor 17 through the electric magnetic starter 35, which completes electrical circuit causing fuel oil pump 11 to force fuel oil through conduit 18. At termination of timer relay 34 phase, pressure switch 30 maintains operation of fuel oil lift pump motor 17, thusly fuel oil tlift pump 11.

Therefore, with fuel oil piping in proper repair, electric service from the utility company provides electrical current through main disconnect switch 32, continued through pressure switch 30 and to fuel oil lift pump motor 17 which, as shown in FIG. 2, completes closed electrical circuit. Should any derangement of the fuel oil piping occur lessening oil pressure on pressure switch 30, the pressure switch would immediately open electrical circuit and cause fuel oil lift pump motor 17 to cease operation, thereby shutting the fuel oil system down.

Electrical wiring diagram, as shown in FIG. 2, in a separate item from furnace wiring circuits and acts independently thereof. Except when derangement of piping occurs, my pressure switch acts as a fuse for the entire oil piping system.

In FIG. 3, an electrical diagram of a single furnace installation is shown. The structural positioning of pressure switch 30, surge chamber 31, and air ventilating valve 23, are the same as heretofore shown for a multiple furnace installation. Instead of several branch conduits 24, with their parts as previously described for the multiple furnace installation, there is just one branch conduit 24 with its parts leading to a single furnace.

With main disconnect switch 32 engaged, thermostat 36 governs the system. Thermostat 36 is a duplex type unit with wiring on one side connected to control the solenoid relay of clock timer 37 and wiring on the other side to operate the circuit of clock timer 37 and continue oircuting to pressure switch 30 et cetera.

With thermostat 36 in open position (above area or room temperature), the solenoid relay is actuated and draws the traveler of clock timer 37 from its spring actuated closed position; with thermostat 36 in closed position (below area or room temperature), wiring to solenoid relay becomes inactive thereby permitting the traveler of clock timer 37 to move toward its contact with wiring from furnace circuit 38 via clock phase of timer 37. During the clock phase of timer 37, oil pump motor 17 and oil pump 11 are started, causing oil to be forced inbo the piping. The electrical circuit remains closed by contact ation from the normal condition of the piping such as a rupture or other break in the piping, or displacement of the parts which would cause lessening of the oil pressure in the piping. Derangement is sometimes referred to in the industry as dearrangement.

Having thus described my invention, I claim:

In a closed pressurized furnace fuel oil piping system having a fuel storage tank containing liquid fuel oil, a motor driven fuel :oil pump, a main conduit having its near end leading from the storage tank, a plurality of spaced furnaces, a plurality of spaced branch oil circuits leading to and from the main conduit and each leading to a furnace, the other and remote end of said main conduit ending in a terminal beyond the last branch oil circuit without a return fuel line therefrom to the storage tank thereby providing a closed system, an electrically operated pressure switch located in the remote end of the main conduit, an electrically operated timer relay connected to the motor of the oil pump and adapted to start the operation of the motor to pump oil through the conduit to thereby apply normal pressure of the oil on said pressure switch and cause it to close the electrical circuit, and maintain the pumping operation, said pressure switch adapted upon lessening of pressure of the oil thereon to open the electrical circuit and stop operation of the lift pump and flow of oil through the system.

References Cited in the file of this patent UNITED STATES PATENTS 1,806,800 Herrenbruck May 26, 1931 1,820,612 Good et al Aug. 25, 1931 2,438,470 Wilson Mar. 23, 1948 

